Ai r F o r c e P ROGRAMS
F-15E Radar Modernization Program (RMP)
Executive Summary
• F-15E Radar Modernization Program (RMP) developmental
flight testing began in January 2011. The RMP demonstrated
incremental progress towards operational effectiveness,
suitability, and mission capability during developmental test
activities throughout FY11. IOT&E is scheduled to begin in
June 2012.
• The Air Force Operational Test and Evaluation Center
(AFOTEC) conducted an Operational Assessment (OA) from
January 5 through April 29, 2011, to assess RMP progress
towards operational effectiveness, suitability, and mission
capability in support of the program’s Milestone C decision.
• During the OA period, RMP demonstrated functional
equivalence to the legacy F-15E radar in some of the system’s
air-to-air modes and made progress in meeting air-to-air
detection and track capabilities under limited and highly
scripted test conditions. However, short range air-to-air
capabilities and air-to-ground capabilities were insufficiently
mature to demonstrate functional equivalence during FY11
developmental flight test.
• Two significant shortfalls were uncovered during FY11
developmental testing: unanticipated electromagnetic
interference (EMI) between the radar and aircraft Ultra High
Frequency (UHF) radio, and aircraft Environmental Control
System (ECS) component failures and in-flight cautions
associated with RMP system integration on the aircraft.
Resolution of these shortfalls is ongoing and should be
completed prior to IOT&E.
System
• The F-15E is a twin engine, tandem seat, fixed wing, all
weather, multi-role fighter aircraft. The F-15E has a fully
missionized cockpit and a multimode air intercept and
air-to-ground radar, giving the aircrew the capability to
employ air-to-air and air-to-ground munitions, a 20-millimeter
cannon, and countermeasures for evading enemy fire.
• The RMP replaces the F-15E legacy APG-70 mechanically
scanned radar with an active electronically scanned array
(AESA) system designated as the APG-82(V)1. The RMP
is designed to retain functionality of the legacy radar system
while providing expanded mission employment capabilities to
include:
- Near-simultaneous interleaving of selected air-to-air and
air-to-ground functions.
- Enhanced air-to-air and air-to-ground classified combat
identification capabilities.
- Longer range air-to-air target detection and enhanced track
capabilities.
- Longer range and higher resolution air-to-ground radar
mapping.
- Improved ground moving target track capability.
• The RMP upgrade is also intended to address legacy F-15E
radar system suitability shortfalls including: poor reliability,
parts obsolescence, and high sustainment costs. The Air Force
intends to retrofit the RMP across the existing F-15E fleet.
• The RMP APG-82(V)1 design leverages capabilities from
currently fielded AESA radar systems. The APG 82(V)1
antenna and power supply are currently in use on the F-15C
APG-63(V)3 program, and the radar receiver/exciter and
Common Integrated Sensor Processor are based on F/A-18E/F
APG-79 AESA system.
• Other hardware and software modifications comprising the
RMP effort include a more powerful ECS, updates to the
aircraft Operational Flight Program and Electronic Warfare
software, a new radio frequency tunable filter, and aircraft
modifications to include a new wideband radome and wiring
changes.
Mission
A unit equipped with the F-15E conducts all weather, day and
night missions to include:
• Offensive and Defensive Counterair
• Conventional Air Interdiction and Nuclear Strike
• Close Air Support and Strike Coordination and
Reconnaissance
• Suppression of Enemy Air Defenses
• Combat Search and Rescue
Major Contractors
• The Boeing Company – Saint Louis, Missouri
• Raytheon – El Segundo, California
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Activity
• The Air Force conducted F-15E RMP testing in accordance
with the DOT&E-approved Test and Evaluation Master Plan
and OA plan.
• The RMP began developmental flight testing on
January 18, 2011. From January through July 2011, the
program completed 48 of 110 planned developmental test
sorties and accrued 178.6 flight test hours.
• AFOTEC conducted an OA from January 5 through
April 29, 2011, to assess RMP progress towards operational
effectiveness, suitability, and mission capability in support
of the program’s Milestone C decision. The OA consisted of
developmental flight testing, hardware-in-the-loop laboratory
testing, and Joint Preflight Integration of Munitions and
Electronics Systems testing to evaluate RMP-configured
F-15E avionics performance in a controlled electromagnetic
environment. The OA flight test encompassed 39 RMP sorties
and 93.2 flight test hours across five early developmental radar
operational flight program software releases.
• During the OA, aircrew observed severe UHF radio noise
when operating in air-to-air modes during flight testing.
Subsequent ground testing revealed that the noise was due to
EMI between the APG-82(V)1 AESA transmitter/receiver and
the radios. To resolve the problem, the program is pursuing
the incorporation of software changes to the radar timeline
and pulse shape in subsequent developmental testing prior to
IOT&E.
• The Air Force Program Executive Office granted Milestone C
approval for RMP in September, 2011, authorizing low-rate
initial production for the first six radar sets.
• IOT&E is currently scheduled to begin in June 2012 and
complete in November 2012.
Assessment
• The RMP demonstrated incremental progress towards
achieving systems operational performance and suitability
goals during FY11 developmental testing.
• During the OA period, the RMP demonstrated legacy
APG-70 radar functionality in long-range air-to-air and some
air‑to‑ground modes as well as progress towards satisfying
other RMP requirements as follows:
- Qualitative aircrew surveys suggest legacy APG-70
pilot‑vehicle interface functionality has been retained. The
RMP demonstrated functional equivalence to APG-70
long-range air-to-air modes and air-to-ground modes and
capabilities. However, RMP within visual range (WVR)
capabilities had not demonstrated similar legacy radar
functionality by the end of the assessment period.
- Limited quantitative performance data indicate basic
long-range air-to-air detection and track capabilities
against non-maneuvering targets are progressing to meet
or exceed RMP specifications. Similarly, air-to-air combat
identification (CID) data indicate early performance is
meeting specification at ranges beyond legacy APG-70
capabilities. However, WVR target acquisition and
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track performance was generally worse than the WVR
capabilities of the legacy APG-70 radar.
- RMP air-to-ground capabilities were relatively immature
during the assessment period, and revealed air-to-ground
map quality and ground moving target track were generally
worse than the legacy APG-70 system.
• Several RMP capabilities were not assessed during the OA
period and remain to be accomplished in post Milestone
C developmental testing. These include: air-to-air and
air-to‑ground weapons employment, electronic warfare
capabilities, and integrated air-to-air and air-to-ground radar
employment in an operationally-representative environment.
• During the OA period, observed system reliability,
maintainability, and availability, suggest the RMP is
progressing towards meeting operational suitability
requirements. However, achieving the Air Force software
stability requirement by IOT&E may not be feasible.
Suitability-related findings from the operational assessment
include the following:
- There were no hardware failures in 130.5 radar operating
hours, suggesting a minimum mean time between
critical failure (MTBCF) of 81.1 hours (80 percent lower
confidence bound) was achieved during the assessment
period.
- The RMP Capabilities Production Document (CPD)
specifies that RMP shall not degrade aircraft availability
below that of legacy APG-70 radar-equipped F-15Es.
Point estimates for aircraft availability (86.7 percent),
aircraft maintainability (15.3 mean maintenance hours per
flight hour), and radar system maintainability (0.13 mean
maintenance hours per flight hour) satisfy that requirement.
- The majority of RMP maintenance activity during the
assessment period was associated with aircraft ECS
component failures and in-flight cautions. Sensitivity of
the legacy ECS avionics cooling monitor unit (ACMU) to
RMP liquid cooling system flow rate fluctuations triggered
numerous ECS cautions during in flight testing. Corrective
action to modify the ACMU and aircraft software interface
is ongoing and must be resolved prior to IOT&E.
- The RMP mean time between software anomaly (MTBSA)
point estimate of 1.15 hours at the end of the assessment
period (within an 80 percent confidence interval of 0.89
to 1.51 hours) is consistent with the program’s projected
software stability at this early stage of development.
However, achieving the RMP CPD requirement of 30 hours
MTBSA at IOT&E will require very aggressive software
stability growth across the remainder of the program’s
developmental test period. The RMP shares over 90
percent software code commonality with the Navy’s F/A18E/F APG-79 radar. Over the past five years, APG-79
software stability has achieved approximately 18 hours
mean operating hours between operational mission failure
despite an accumulated 100,000 fleet flight hours. Given
RMP’s commonality with the APG-79, the pending
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incorporation of air-to-ground CID and RMP anti-tamper
software capabilities, and the aggressive MTBSA growth
path required in the remaining developmental test period,
the Air Force is not likely to meet the 30 hour MTBSA
requirement.
- Unexpected EMI between the RMP and the F-15E UHF
radios occurred during the assessment period. When
operating in air-to-air modes, UHF noise severely impeded
aircrew operations. Since the end of the assessment period,
the Air Force has conducted ground tests indicating radar
software changes should reduce or eliminate the EMI
without adversely affecting RMP performance. Resolution
of this EMI problem is required prior to IOT&E.
Recommendations
• Status of Previous Recommendations. This is the first annual
report for this program.
• FY11 Recommendations. The Air Force should:
1. Continue to address and resolve ECS and UHF EMI
shortfalls identified during the OA prior to IOT&E.
2. Consider either amending the RMP 30-hour MTBSA
requirement or structuring the program (in particular,
adding time and resources for additional development) such
that it is able to achieve the desired performance measure.
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